Duqu spawned by 'well-funded team of competent coders'

World's first known modular rootkit does steganography, too

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The Duqu malware that targeted industrial manufacturers around the world contains so many advanced features that it could only have been developed by a team of highly skilled programmers who worked full time, security researchers say.

The features include steganographic processes that encrypt stolen data and embed it into image files before sending it to attacker-controlled servers, an analysis by NSS researchers found. Using a custom protocol to hide the proprietary information inside the innocuous-looking file, before it's sent to command and control servers, is a centuries-old technique used to conceal the exchange of sensitive communications.

Duqu is also the world's first known modular plugin rootkit, the researchers said. That allows the attackers to add or remove functionality and change command and control servers quickly with little effort. The conclusion the researchers draw from their analysis is that Duqu is the product of well organized team of highly motivated developers.

“Given the complexity of the system (solid driver code plus impressive system architecture) it is not possible for this to have been written by a single person, nor by a team of part-time amateurs,” NSS researchers Mohamed Saher and Matthew Molinyawe wrote. “The implication is that, given the requirement for multiple man-years of effort, that this has been produced by a disciplined, well-funded team of competent coders.”

The modular design means that there's a potentially large number of components that have yet to be discovered. NSS has released a scanning tool that can detect all Duqu drivers installed on an infected system. The tool doesn't generate false positives and has already been used to spot two previously undetected Duqu drivers, the researchers said.

“We hope the research community can use this tool to discover new drivers and would ask that any samples be provided to NSS researchers (anonymously if preferred) in order to aid us in understanding more about the threat posed by Duqu,” they wrote.

The researchers echoed previous reports that Duqu contains many similarities to the Stuxnet worm used to sabotage uranium enrichment plants in Iran. The NSS analysis said Duqu uses similar code and techniques to those of Stuxnet, but they said there's not enough evidence to say Duqu is derived from Stuxnet.

“Many researchers are claiming definitively that the Duqu authors had access to the original Stuxnet source code,” they wrote. “This has not been proven. It is possible for anyone to reverse engineer the original Stuxnet code to the point where it can be modified and recompiled.”

If at the end of all of this you're left scratching your head, you're in good company. Duqu's state-of-the-art design and its resemblance to Stuxnet makes the malware worth watching, but with key questions still unanswered, it's too early to know exactly what to think.

“There is no possible explanation for the production of such a sophisticated and elegant system merely to steal the information that has been targeted so far,” they wrote. “Why go to all this trouble to deploy a simple key-logger? Given that there are additional drivers waiting to be discovered, we can liken Duqu to a sophisticated rocket launcher – we have yet to see the real ammunition appear.” ®